Exploration in the service of prospective control

We propose a sequential process of exploration that can account for percept ion-action coupling in infant locomotion. Each phase in the sequence is a p rocess of obtaining progressively more information leading to a motor decis ion-exploration from a distance, exploration via direct contact, and explor ation of alternative means. Quick glances and prolonged looking from afar s erve to alert the perceiver to important changes in the terrain. Intentiona l touching and testing alternative ways to traverse an obstacle are only pr ompted when prior information indicates a potential threat to balance. We f urther propose that depth information is privileged because it can be detec ted from a distance more readily than other surface properties such as rigi dity and friction. Studies of infants walking down slopes and across "hole/ patch" transitions illustrate the important role of exploration in prospect ive control of locomotion. (C) 2000 Elsevier Science Inc. All rights reserv ed.